<template>
  <div class="xtx-carousel" @mouseenter="stop" @mouseleave="play">
    <ul class="carousel-body">
      <li class="carousel-item" :class="{fade: active === index}" v-for="(item, index) in slides" :key="item.id">
        <RouterLink :to="item.hrefUrl">
          <img
            :src="item.imgUrl"
            alt=""
          />
        </RouterLink>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="prev">
      <i class="iconfont icon-angle-left"></i>
    </a>
    <a href="javascript:;" class="carousel-btn next" @click="next">
      <i class="iconfont icon-angle-right"></i>
    </a>
    <div class="carousel-indicator">
      <span v-for="(item, index) in slides" :key="item.id" :class="{active : active === index}" @mouseenter="active = index"></span>
    </div>
  </div>
</template>

<script>
import { ref, onMounted, onUnmounted } from 'vue'
export default {
  name: 'XtxCarousel',
  props: {
    slides: {
      type: Array,
      default: () => []
    },
    autoplay: {
      type: Boolean,
      default: true
    },
    duration: {
      type: Number,
      default: 3000
    }
  },
  setup (props) {
    // 高亮
    const active = ref(0)

    // 左右箭头
    const prev = () => {
      if (active.value === 0) {
        active.value = props.slides.length - 1
      } else {
        active.value--
      }
    }
    const next = () => {
      if (active.value === props.slides.length - 1) {
        active.value = 0
      } else {
        active.value++
      }
    }

    // 轮播图播放逻辑
    let timer = null
    const play = () => {
      if (!props.autoplay) return
      // 防止开启多个定时器
      clearInterval(timer)
      timer = setInterval(() => {
        active.value++
        // 判断边界
        if (active.value >= props.slides.length) {
          active.value = 0
        }
      }, props.duration)
    }

    const stop = () => {
      clearInterval(timer)
    }

    // 组件渲染时，开启轮播图
    onMounted(() => {
      play()
    })
    // 组件销毁时，关闭轮播图
    onUnmounted(() => {
      stop()
    })
    return {
      active,
      prev,
      next,
      play,
      stop
    }
  }
}
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>
